Since our recent work suggests that prostaglandin A may respond to changes in sodium intake and influence aldosterone seretion, projects to measure and study PG metabolism have been developed. A radioimmunoassay for PGA1, has been developed. Additionally, in vivo studies of PGA turnover, metabolic clearance, and the effect of lung, liver, and renal metabolism has been defined. A study of renin and aldosterone levels in patients with inappropriate antiduiretic hormone excess has been completed and published. A study of the role of aldosterone in hepatic ascites is being prepared for publication.